Patent Fundamentals Toolkit: Eligibility, Novelty, Obviousness, and Disclosure

By Casey Scott McKay · 2026-02-06

Four questions decide whether an invention can be patented and how broadly, and every later dispute is a rerun of one of them. This toolkit maps eligibility, novelty, obviousness, and disclosure - what each asks, what evidence answers it, and where the four interact - and routes each to the Marksy documents that do the work. It explains why eligibility is decided on the claim language rather than on the technology, why the first-to-file system made the filing date the single most consequential date in a company's intellectual property calendar, and why the disclosure requirements set a ceiling on claim scope that no amount of prosecution skill can raise. It treats the grace period honestly, walks the four sequences that lose patent rights before anyone files, and closes with the reading path, the authorities table, and the forms. It is written for the counsel deciding whether to file and for the litigator reading a patent for the first time.

IP and Technology > Patent Counseling Transactions | Toolkit | Published 6 February 2026 - Updated 13 April 2026 | Casey Scott McKay - marksy.us

Summary. Four questions decide whether an invention can be patented and how broadly, and every later dispute is a rerun of one of them. This toolkit maps eligibility, novelty, obviousness, and disclosure — what each asks, what evidence answers it, and where the four interact — and routes each to the Marksy documents that do the work. It explains why eligibility is decided on the claim language rather than on the technology, why the first-to-file system made the filing date the single most consequential date in a company's intellectual property calendar, and why the disclosure requirements set a ceiling on claim scope that no amount of prosecution skill can raise. It treats the grace period honestly, walks the four sequences that lose patent rights before anyone files, and closes with the reading path, the authorities table, and the forms. It is written for the counsel deciding whether to file and for the litigator reading a patent for the first time.

Keywords: patent eligibility · abstract idea · natural phenomenon · novelty · prior art · on-sale bar · public use · grace period · obviousness · motivation to combine · objective indicia · enablement · written description · definiteness · means plus function · claim scope · specification support · inventorship · provisional application · priority chain

Start Here

On a Monday in March, Halverson Instruments — a sixty-person maker of industrial sensing equipment — has four patent problems that nobody has framed as patent problems.

An engineer has developed a method of calibrating a sensor array that reduces drift by a third. She described it at a trade conference eleven months ago. Nobody was in the room from legal.

The company's chief technology officer wants to patent "using machine learning to predict maintenance intervals," which is how he describes it and how the draft application describes it.

A competitor's patent was found in a customer's request for proposal, and it appears to cover the company's existing product. Nobody has read the claims; someone read the abstract.

And the company's largest customer has asked, in a supply agreement, for a representation that the company's products do not infringe any third-party patent and that its own patents are valid.

Four problems, four different doctrines, and one thing in common: each is decided by a question that could have been answered before it became urgent.

This toolkit answers three questions.

Can this be patented at all? Eligibility asks whether the claimed subject matter is the kind of thing patents cover. It is decided on the claim language, not on how impressive the technology is.
Is it new and non-obvious, as of when? Novelty and obviousness are both measured against prior art as of the effective filing date, which makes that date the most consequential number in the file.
How broadly can it be claimed? The disclosure requirements set a ceiling. A claim broader than what the specification enables and describes is invalid regardless of how it was allowed.

If you read only one thing, read The Bargain of Disclosure. The distinction between an idea and a claimed invention is what every one of Halverson's four problems turns on.

The Four Questions

Question one: eligibility

What it asks. Whether the claimed subject matter falls within the statutory categories and outside the judicial exceptions.

The statute. 35 U.S.C. § 101 permits a patent on any new and useful process, machine, manufacture, or composition of matter, or any new and useful improvement.

The exceptions. Laws of nature, natural phenomena, and abstract ideas are not patentable, however new and useful. This is judge-made and it is where the analysis actually happens.

The framework. First, is the claim directed to one of the exceptions? Second, if so, do the claim elements — individually and as an ordered combination — amount to significantly more than the exception itself, transforming it into a patent-eligible application?

What fails. Claims reciting a result rather than a mechanism. Claims implementing a known business practice on generic computing components. Claims to a mathematical relationship with instructions to apply it. Claims to collecting, analyzing, and displaying data without a specific technical improvement.

What passes. Claims reciting a specific technical arrangement that improves how a machine operates. Claims to a particular way of achieving a result rather than the result itself. Claims whose specification describes a technical problem and a technical solution in technical terms.

The practical instruction. Eligibility is decided on the claim language and heavily influenced by the specification's framing. A specification describing a business advantage and treating the implementation as conventional supplies the defendant's argument. One describing a technical problem and a specific solution supplies the patentee's.

See What Can Actually Be Patented.

Question two: novelty

What it asks. Whether a single prior art reference discloses every element of the claim, arranged as claimed.

The statute. 35 U.S.C. § 102, in its post-America Invents Act form, bars a patent where the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date.

What counts as prior art. Patents and published applications anywhere. Printed publications anywhere, in any language. Public use and sales activity. Anything otherwise available to the public. And earlier-filed applications that later publish or issue.

The grace period. 35 U.S.C. § 102(b) supplies a one-year grace period for disclosures made by the inventor or derived from the inventor, and for subsequent third-party disclosures after such a disclosure. It is narrower than the pre-2013 grace period, it does not exist in most other countries, and relying on it forfeits foreign rights in nearly every jurisdiction that matters.

The on-sale and public use bars. A commercial offer for sale of an invention ready for patenting starts the clock, and the sale need not disclose the invention. A confidential sale can trigger the bar. This is the sequence that catches companies most often, because engineers and sales teams do not think of a quote as a legal event.

The practical instruction. File before disclosing, before offering, and before using publicly. The grace period is a repair mechanism, not a plan.

See The Priority Chain.

Question three: obviousness

What it asks. Whether the differences between the claimed invention and the prior art are such that the invention as a whole would have been obvious to a person of ordinary skill in the art at the time.

The statute. 35 U.S.C. § 103.

The framework. Determine the scope and content of the prior art, the differences between it and the claims, and the level of ordinary skill; then evaluate obviousness against that background, considering objective indicia.

Where it is won and lost. The motivation to combine. A reference disclosing element A and another disclosing element B does not make A-plus-B obvious without a reason a skilled artisan would have combined them and a reasonable expectation of success. Shared field of endeavor is not a reason, and it is the reason offered most often.

Objective indicia. Commercial success, long-felt but unmet need, failure of others, industry praise, licensing, and copying — each requiring a nexus to the claimed features rather than to marketing or price. This evidence is available to the patentee and unavailable to the challenger, and it is underused.

Teaching away and unexpected results. A reference discouraging the combination, or a result the skilled artisan would not have predicted, both weigh against obviousness and both must be established on the record.

The practical instruction. Obviousness is the ground on which most patents are actually invalidated, and it is answered by the quality of the prosecution record more than by anything done later.

Question four: disclosure

What it asks. Whether the specification teaches how to make and use the full scope of what is claimed, shows the inventor possessed it, and defines the claim's boundaries.

The statute. 35 U.S.C. § 112. Subsection (a) carries enablement and written description; subsection (b) carries definiteness; subsection (f) governs means-plus-function claiming.

Enablement. The specification must enable a skilled artisan to make and use the claimed invention without undue experimentation, across the claim's full scope. A claim to a genus supported by one species is the classic failure.

Written description. The specification must show the inventor possessed the claimed invention as of the filing date. Distinct from enablement, and it is what defeats claims added later by amendment to cover a competitor's product.

Definiteness. The claims, read in light of the specification and prosecution history, must inform a skilled artisan about the scope with reasonable certainty. Terms of degree are not automatically indefinite; terms with no objective boundary are.

Means-plus-function. A claim element expressed as a means for performing a function is construed to cover the structure described in the specification and equivalents. For a computer-implemented function the structure is the algorithm, and a specification that describes only a processor is indefinite.

The practical instruction. The disclosure requirements set a ceiling on claim scope. Everything about later claim breadth was determined by what the specification said on the filing date.

See Drafting a Patent Specification That Survives.

How the Four Interact

| Question | Statute | Measured as of | Decided on | Fixable later? | |---|---|---|---|---| | Eligibility | 35 U.S.C. § 101 | Any time | Claim language and specification framing | Partly, by amendment | | Novelty | 35 U.S.C. § 102 | Effective filing date | Prior art references | No | | Obviousness | 35 U.S.C. § 103 | Effective filing date | Prior art plus motivation | Partly, by narrowing | | Disclosure | 35 U.S.C. § 112 | Filing date | The specification as filed | No |

The interactions that matter.

Broadening to avoid obviousness creates disclosure problems. A claim broadened to distinguish over art must still be enabled and described.

Narrowing to avoid art creates estoppel. A narrowing amendment for patentability surrenders equivalents in the territory given up.

Eligibility and disclosure pull together. A specification that describes a specific technical mechanism helps eligibility and supports the claims. One that describes a result at a high level hurts both.

Novelty and the grace period interact with foreign filing. A disclosure covered by the domestic grace period destroys novelty in most other countries.

The Four Sequences That Lose Rights

The conference presentation. An engineer describes the work publicly. The domestic grace period runs one year; foreign rights are gone immediately. The fix is a filing before the abstract is submitted, and a policy that routes every external presentation past someone who knows this.

The quote. Sales issues a commercial offer for an invention ready for patenting. The clock starts, confidentiality does not save it, and nobody records the date. The fix is a trigger in the quoting process for products embodying unfiled inventions.

The joint development disclosure. Technology shared with a partner under an agreement that addresses confidentiality and says nothing about filing. Either party may file, an inventorship dispute follows, and the remedies are narrow. 35 U.S.C. § 135; 35 U.S.C. § 291. See Whose Invention Is It.

The missing assignment. The inventor never executed a present-tense assignment, so the company owns nothing. 35 U.S.C. § 261. Discovered in diligence, years later.

Inventorship and Ownership

Inventorship is a legal test. A person who contributed to the conception of the subject matter of at least one claim is an inventor. Funding, direction, management, and reduction to practice under supervision do not qualify. 35 U.S.C. § 116.

It is determined claim by claim, which means it changes as claims are amended during prosecution.

Errors are correctable under 35 U.S.C. § 256 where they arose without deceptive intent, and correction is easier before a dispute than after.

Ownership follows inventorship, then assignment. An inventor owns until they assign, and assignment requires a writing. Present-tense language transfers; a promise to assign in the future does not.

Joint ownership is the default nobody wants. Each co-owner may practice and license independently without accounting, and all must join to sue. 35 U.S.C. § 262.

The declaration. Each inventor must execute an oath or declaration under 35 U.S.C. § 115, and substitute statements are available where an inventor is unavailable or refuses.

The Duty of Candor

What it requires. Each individual associated with filing and prosecution owes a duty of candor and good faith, including a duty to disclose information material to patentability. 37 C.F.R. § 1.56.

How it is satisfied. An information disclosure statement, timed and formatted under 37 C.F.R. § 1.97 and 37 C.F.R. § 1.98.

What must be disclosed. Prior art known to anyone with the duty, including art cited in related applications, art from foreign counterparts, and art disclosed in litigation. Not a search obligation — a disclosure obligation for what is known.

Why it matters disproportionately. Inequitable conduct renders the entire patent unenforceable, and it can reach related patents. It requires proof of a material omission and specific intent to deceive, which is a demanding standard and a devastating outcome.

The practical instruction. Disclose more rather than less, keep a record of what was considered and when, and treat art surfacing in one family member as art for the whole family.

Reading a Patent for the First Time

Start with the claims, not the abstract. The claims define the right; everything else is context.

Read claim 1 and identify each limitation by breaking at every functional requirement rather than at every comma.

Check the term and the front page. Filing date, priority claims, expiration, terminal disclaimers, and maintenance fee status. 35 U.S.C. § 154; 35 U.S.C. § 41.

Pull the file wrapper. The references the examiner cited, the rejections, the amendments, and the arguments. The amendment that produced allowance identifies the point of novelty, and the arguments limit the claims.

Check the assignment records for the chain of title.

Check for continuations, because a live continuation means new claims can still be drafted against a competitor's product.

Then, and only then, read the specification for what it enables and describes.

Building the Program

An invention disclosure process that engineers actually use, with a short form and a fast response.

A review cadence — monthly or quarterly — where disclosures are triaged: file, keep as a trade secret, publish defensively, or do nothing.

Trigger points in the business process. Conference abstracts, customer quotes, product launches, and partner disclosures each route to counsel before they happen.

A prior art awareness practice, so that art known to the company reaches the file under the duty of candor.

Assignment hygiene. Present-tense language, executed at hire, with a confirmatory assignment at filing.

A docketing system for provisional conversions, foreign filing deadlines, office action responses, and maintenance fees.

A budget model. Filing, prosecution, issuance, and maintenance over twenty years, per family, per country.

An annual portfolio review deciding what to maintain, what to abandon, and what to file next. See Patent Portfolio Management Toolkit.

What a Patent Is, Commercially

The doctrine describes a right. The business question is what the right does, and four things are worth stating plainly to a client who has not held one before.

It is a right to exclude, not a right to practice. A patent does not license its owner to make anything. A company can hold a patent on its product and still infringe someone else's. This is why freedom-to-operate analysis is a separate exercise from patenting, and why the two are confused constantly.

It expires. Twenty years from the earliest non-provisional filing date, subject to adjustment and terminal disclaimers, and subject to maintenance fees at defined intervals. 35 U.S.C. § 154; 35 U.S.C. § 41. A twenty-year term sounds long and is short against a development cycle that consumes five of it.

It is territorial. A domestic patent stops nothing abroad. Foreign protection requires foreign filings, and the deadline to preserve that option runs twelve months from the first filing under 35 U.S.C. § 119.

It publishes. An application publishes at eighteen months under 35 U.S.C. § 122, which teaches competitors what the company is doing and ends any trade secret in the disclosed subject matter. Non-publication requests are available only where no foreign filing will occur.

What it is worth depends on what it covers, not on what it is about. A patent whose claims read on a competitor's product is valuable. A patent describing the same technology whose claims read only on the company's own implementation is a certificate. The difference is decided in claim drafting and prosecution, and it is invisible on the front page.

The costs are recurring. Filing, prosecution, issuance, and maintenance across the term and across countries. A family filed in five jurisdictions costs a multiple of a domestic-only filing every year for two decades, which is why the annual pruning review matters.

The Provisional Application, Used Properly

What it is. A filing under 35 U.S.C. § 111(b) that establishes a priority date, is never examined, never publishes, and expires in twelve months.

What it is for. Buying twelve months before the non-provisional decision, establishing a date before a disclosure, and starting the clock on foreign filing options.

What it is not. A cheap patent. The priority it confers extends only to subject matter it actually describes and enables. A two-page provisional supporting a forty-page non-provisional confers priority on two pages' worth of subject matter, and the rest gets the later date.

The recurring failure. A provisional drafted as a placeholder — slides, a paper, an invention disclosure form — followed by a non-provisional with real claims that the provisional does not support. The company believes it has an earlier date and does not.

The discipline. Draft the provisional as though it were the specification, because for priority purposes it is. Include the embodiments, the ranges, the alternatives, and the technical detail. It costs more than a placeholder and it is the difference between a date and the illusion of one.

The twelve-month decision. Convert, refile with new matter and a new date for that matter, or abandon. Missing it forfeits the priority claim entirely, and the intervening disclosures become prior art.

Foreign filing runs on the same clock. Twelve months to file abroad or under the treaty, measured from the provisional. See International Patent Toolkit.

Claim Drafting, in Four Principles

Claim drafting is a specialist skill and four principles explain most of what separates a valuable claim from a decorative one.

Claim the invention, not the product. A claim reciting every feature of the commercial embodiment is easy to allow and easy to avoid. The claim should recite what is inventive and nothing else, because every additional limitation is another way for a competitor to escape.

Claim at multiple levels. Independent claims at different breadths, with dependent claims adding limitations in a considered order. When the broadest falls to prior art, the next one down should still cover the competitor.

Claim the component where the invention lives. A claim to a system containing an inventive module is infringed only by someone selling the whole system. A claim to the module is infringed by the module's maker, it is easier to chart, and it prices better in damages because the royalty base starts at the component. See What a Patent Is Worth in Court.

Claim in every statutory form the invention supports. Apparatus, system, method, and where applicable a computer-readable medium. Method claims escape the marking requirement and carry divided-infringement risk; apparatus claims carry the marking obligation and avoid the actor problem. A family with both has options a family with one does not.

And one rule about actors. Every method claim should be readable as performed by a single entity. A claim reciting steps by a server operator and an end user is a claim a defendant will attack on the pleadings, and the fix at drafting is free.

The Prosecution Record as an Asset

Everything said during prosecution is public, permanent, and read by adversaries.

Amendments narrow claims and surrender equivalents. A narrowing amendment for patentability creates a presumption of surrender in the territory given up, which is why every amendment should be made with the eventual infringement theory in mind.

Arguments limit claims without amending them. A clear statement distinguishing a reference constrains the claim's scope in litigation as effectively as an amendment.

The examiner's reasons for allowance sit in the file and are quoted back at claim construction.

The references considered establish what the Office saw, which matters when a challenger tries to use the same art at the Board and faces a discretionary denial argument.

Interviews should be summarized carefully, because the summary is the record of what was said.

Continuations keep the family alive, permitting new claims drafted against a competitor's product later. A family with no pending continuation is a family that cannot respond to a competitor's design-around.

The practical instruction. Prosecute with a litigator's eye. The file wrapper is written once and read for twenty years. See Inside Patent Prosecution.

Halverson's Four Problems, Answered

The conference presentation. The engineer described the calibration method publicly eleven months ago. Domestically, the grace period under 35 U.S.C. § 102(b) leaves one month to file. Abroad, the rights are gone in nearly every jurisdiction that matters, because the grace period is a domestic feature and most countries apply absolute novelty. The answer is a provisional filed this week, drafted as a real specification rather than a placeholder, and a policy routing every external presentation past counsel before the abstract is submitted.

The machine learning application. "Using machine learning to predict maintenance intervals" is a result described at the level of a business objective, implemented on generic components, and it is the profile that fails eligibility under 35 U.S.C. § 101. The answer is not to abandon the filing; it is to find the technical mechanism. What specifically does the system do that a general-purpose approach does not — a particular feature representation, a specific sensor fusion arrangement, a training regime that solves a technical problem in the measurement chain? Claim that, and describe the technical problem and the technical solution in the specification. A specification framed around business benefit supplies the defendant's argument before anyone drafts a claim.

The competitor's patent. Somebody read the abstract, which is the part of a patent that describes what it is about rather than what it covers. The answer is to read claim 1, break it at every limitation, and compare each against the product. Then pull the file wrapper, because the amendment that produced allowance identifies the point of novelty and the arguments limit the claims. Then check the term, the maintenance fees, and the assignment records. Half of these exercises end with a conclusion that the claim does not read on the product, and the other half produce a design-around that costs an engineering change. See Freedom-to-Operate Checklist.

The customer's representation. A warranty of non-infringement against any third-party patent is a warranty nobody can honestly give, because it asserts a negative about an unbounded universe. The negotiated position is a representation limited to the company's actual knowledge, an indemnity with a cap and defined procedures, and a carve-out for the customer's own specifications and combinations. Where the customer will not move, the price of the warranty should reflect what is being underwritten. The other half of the same clause — a representation that the company's own patents are valid — is equally unavailable, because validity is presumed under 35 U.S.C. § 282 and never guaranteed.

What the four have in common. Each was a legal event that occurred inside a business process — a conference submission, a product description, a request for proposal, a supply negotiation — and in each case the process ran without anyone who knew it was a legal event. Building the trigger points described above is the entire preventive program, and it costs less than any one of the four problems.

What the Four Questions Cost

Budgeting a patent program requires knowing where the money goes, and it is not distributed the way clients expect.

Eligibility costs almost nothing to assess and a great deal to get wrong. An hour with the claims and the specification framing, early, prevents an application that will be rejected repeatedly and a patent that will not survive a motion.

Novelty costs a search. A targeted search against the point of novelty, commissioned before drafting, is modest and it informs both whether to file and how to claim. A search commissioned after an office action is the same money spent later with less benefit.

Obviousness costs prosecution. It is the ground on which most applications are rejected and most patents are invalidated, and the expense is in the back-and-forth: responses, amendments, interviews, and sometimes an appeal. A well-drafted application with claims at multiple breadths reduces this substantially.

Disclosure costs drafting time, and it is the one place where spending more at the start reliably returns more later. A specification with the embodiments, the ranges, the alternatives, and the technical detail supports broader claims, survives later amendment, and gives continuations something to claim.

The recurring costs are maintenance and foreign. Fees at defined intervals under 35 U.S.C. § 41, multiplied by every country. This is where portfolios become expensive and where the annual pruning review earns its keep.

The allocation rule. Spend on the search and on the specification, economize on the number of filings rather than on the quality of each, and prune aggressively at each maintenance window. A company with twelve well-drafted families is in a better position than one with forty thin ones costing the same.

A Suggested Reading Path

If you are deciding whether to file:

The Bargain of Disclosure — what the right actually is.
What Can Actually Be Patented — whether it can be patented at all.
The Priority Chain — the dates that decide everything.
Prior Art and Patentability Checklist — the box-by-box version.

If you are drafting or prosecuting:

If you are reading someone else's patent:

Primary Authorities

| Authority | Proposition | |---|---| | 35 U.S.C. § 101 | Eligible subject matter; judicial exceptions | | 35 U.S.C. § 102 | Novelty; prior art; grace period; on-sale bar | | 35 U.S.C. § 103 | Obviousness | | 35 U.S.C. § 112 | Enablement, written description, definiteness, means-plus-function | | 35 U.S.C. § 111 | Application requirements | | 35 U.S.C. § 115 | Inventor's oath or declaration | | 35 U.S.C. § 116 | Joint inventors | | 35 U.S.C. § 119 | Foreign and provisional priority | | 35 U.S.C. § 120 | Benefit of an earlier application | | 35 U.S.C. § 122 | Publication at eighteen months | | 35 U.S.C. § 135 | Derivation proceedings | | 35 U.S.C. § 154 | Term and provisional rights | | 35 U.S.C. § 256 | Correction of inventorship | | 35 U.S.C. § 261 | Assignment in writing | | 35 U.S.C. § 262 | Joint owners | | 35 U.S.C. § 271 | Infringing acts | | 35 U.S.C. § 282 | Presumption of validity; defenses | | 35 U.S.C. § 291 | Derived patents | | 35 U.S.C. § 41 | Maintenance fees | | 37 C.F.R. § 1.56 | Duty of disclosure | | 37 C.F.R. § 1.97 | Information disclosure statement timing | | 37 C.F.R. § 1.98 | Information disclosure statement content | | 37 C.F.R. § 1.75 | Claim form |

Forms and Templates

The Assignment Agreement Template supplies the present-tense assignment language that makes ownership work, and it should be executed at hire rather than at filing. The Portfolio Inventory Template is the register that supports the annual review, tracking family, jurisdiction, status, deadline, and budget. The License Agreement Template is the starting point for out-licensing once rights exist, and it is worth reading early because the license terms a company will want inform the claims it should be seeking. The Office Action Response Template structures the response so that arguments are made once, clearly, with the amendment and the reason for it stated in a way the file wrapper will read well in litigation years later.

Related Toolkits and Checklists

For the mechanics of getting an application allowed, the Patent Prosecution Toolkit takes over where this one ends. For clearing a product against others' patents, use the Freedom-to-Operate and Patent Clearance Toolkit. For filing abroad, the International Patent Toolkit covers the treaty routes and the country decisions. For managing what a company already holds, the Patent Portfolio Management Toolkit supplies the harvest, budget, and pruning disciplines. And for the threshold question of whether a patent is the right instrument at all, the Choosing Your Protection Toolkit runs the comparison against copyright, trademark, and trade secrecy.